Just come across some negative seo (yes it does exist) where by exerts of your content is scraped and posted on various urls without backlinks, my response was swift to this filed a dmca and spam reports.
The site targeted by neg seo has dropped out of the index for main keyword. Difficult with so many updates to discover if this is the real cause or if its something else but I guess you have to cover all bases.
Just wanted to give you guys a heads up on this technique.